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1.
Int J Surg Case Rep ; 115: 109299, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38277986

RESUMO

INTRODUCTION AND IMPORTANCE: A hydrocele is typically a non-cancerous condition that arises from the accumulation of fluid between the layers of the vaginal process. Diagnosis primarily involves a physical examination. In instances where the condition is mistaken for other pathological conditions, additional investigations may be undertaken. Surgical intervention is typically deferred until after the age of one year, unless the hydrocele is significantly large. CASE PRESENTATION: A case was presented of a 4-year-old boy who was referred to the hospital with a suspected deep inguinal hernia. Upon examination, it was determined that the mass was actually an encysted hydrocele of spermatic cord. The patient underwent a minimally invasive surgery to remove the spermatocele, and the procedure was successful. CLINICAL DISCUSSION: This emphasizes the importance of obtaining a detailed patient history and conducting a comprehensive physical examination, which often provide sufficient information to make a diagnosis. In many instances, these initial steps can spare patients from undergoing additional tests that may be invasive or pose unnecessary risks. CONCLUSION: It is important to note that in cases of hydroceles, conservative treatment, such as observation, is the primary approach before the age of one year. Surgery is typically reserved for older children or those with large hydroceles.

2.
Appl Radiat Isot ; 204: 111147, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38113663

RESUMO

BACKGROUND AND AIM: Spiral computed tomography (CT) scans, which are considered a high-contrast resolution, quick and cross-sectional imaging technique, have grown in popularity as a result of technological advancements. However, these advancements have brought with them the potential for significantly increased radiation doses to the patient. Consequently, many organizations recommended optimization and establishing diagnostic reference levels. The aim of the current study was to assess CT radiation dose and propose a local diagnostic reference level (LDRL) for the adult trunk [chest and abdomen] using CT dose parameters such as CT dose index volume (CTDIvol) and dose length product (DLP) as well as to compare the practices for aforementioned examinations between two hospitals in Taif and Abha cities in Saudi Arabia. MATERIALS AND METHODS: Data from 428 patients (216 for abdomen and 212 for chest) who were examined in two hospitals in Taif and Abha City in Saudi Arabia from December 2022 to March 2023, are used in this study. The data for hospitals in Taif and Abha are presented as 'T' and 'A' throughout this manuscript. The parameters of exposure and slice thickness were recorded in a specially designed data sheet together with the gender, age and patients morphometric. Microsoft Excel version 2010 was used to analyze results and plot the figures. The LDRL was achieved from the third quartile of CTDIvol and DLP for each hospital and examination. RESULTS: The average DLP (mGy-cm) and CTDIvol (mGy) for the chest and abdomen were 243 mGy cm, 5.8 mGy and 549 mGy cm, 8.6 mGy respectively. The average effective dose (ED) for chest and abdomen were 5.10 and 21.10 mSv, respectively. The proposed LDRL for the chest and abdomen were 6.9 mGy (CTDIvol), 375 mGy-cm (DLP), 7.8 mGy (CTDIvol), and 747 (DLP) mGy-cm, respectively. CONCLUSION: Hospital 'A' irradiated patients with a higher dose for the abdomen exam than Hospital 'T', but both hospitals agreed on the amount of radiation dose received by patients for chest imaging. The proposed LDRL for two examinations was less than the DRL obtained from the literature.


Assuntos
Níveis de Referência de Diagnóstico , Tomografia Computadorizada por Raios X , Adulto , Humanos , Arábia Saudita , Cidades , Doses de Radiação , Tomografia Computadorizada por Raios X/métodos , Abdome/diagnóstico por imagem , Valores de Referência
3.
Open Access Emerg Med ; 15: 465-471, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-38145228

RESUMO

Purpose: To examine the validity and predictability of thrombolysis in myocardial infarction (TIMI) risk and HEART scores in patients presenting to the emergency department (ED) with chest pain in Jordan (representative of the Middle East and North Africa Region, MENA). Patients and Methods: Risk scores were calculated for 237 patients presenting to the ED with chest pain. Patients were followed-up prospectively for the need for percutaneous coronary intervention, major adverse cardiovascular events, and all-cause mortality, looking for correlation and accuracy between the predicted cardiovascular risk from TIMI risk score and HEART score and the clinical outcome. Results: Of the 237 patients, approximately 77% were diagnosed with unstable angina and 23% diagnosed with non-ST elevation myocardial infarction (NSTEMI). about two thirds of the study population were smokers and known to have hypertension and dyslipidaemia. In 50 patients, the primary outcome (need for percutaneous coronary intervention (PCI) and/or major adverse cardiovascular events (MACE) at days 14 and 40, all-cause mortality) was observed. Regarding the predictability of the TIMI score, a larger number of events were observed in the study population than predicted. Patients with TIMI scores of 3 to 5 have about a 5-8% higher event rate than predicted. Conclusion: Both TIMI and HEART risk scores were able to predict an elevated risk of major cardiovascular adverse events (MACE). The overall impression was that the TIMI risk score tended to underestimate risk in the study population.

4.
Front Bioeng Biotechnol ; 11: 1153969, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37324440

RESUMO

Introduction: The metal-organic frameworks (MOF) have shown fascinating possibilities in biomedical applications, and designing a drug delivery system (DDS) based on the MOF is important. This work aimed at developing a suitable DDS based on Denosumab-loaded Metal Organic Framework/Magnesium (DSB@MOF (Mg)) for attenuating osteoarthritis. Materials and Methods: The MOF (Mg) (Mg3(BPT)2(H2O)4) was synthesized using a sonochemical protocol. The efficiency of MOF (Mg) as a DDS was evaluated by loading and releasing DSB as a drug. In addition, the performance of MOF (Mg) was evaluated by releasing Mg ions for bone formation. The MOF (Mg) and DSB@MOF (Mg) cytotoxicity towards the MG63 cells were explored by MTT assay. Results: MOF (Mg) characterized by using XRD, SEM, EDX, TGA, and BET. Drug loading, and releasing experiments proved that DSB was loaded on the MOF (Mg) and approximately 72% DSB was released from it after 8 h. The characterization techniques showed that MOF (Mg) was successfully synthesized with good crystal structure and thermal stability. The result of BET showed that MOF (Mg) had high surface areas and pore volume. This is the reason why its 25.73% DSB was loaded in the subsequent drug-loading experiment. Drug release and ion release experiments indicated DSB@MOF (Mg) had a good controlled release of DSB and Mg ions in solution. Cytotoxicity assay confirmed that the optimum dose of it had excellent biocompatibility and could stimulate the proliferation of MG63 cells as time went on. Conclusion: Due to the high loading amount of DSB and releasing time, DSB@MOF (Mg) can be promising as a suitable candidate for relieving bone pain caused by osteoporosis, with ossification-reinforcing functions.

6.
Asian Pac J Cancer Prev ; 24(1): 223-229, 2023 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-36708571

RESUMO

BACKGROUND: Serum Prostate-specific antigen (PSA) has been used for screening and diagnosis of prostate cancer (PCa) but it is burdened by its low accuracy, creating a need for reliable diagnostic markers. Despite prostate-specific membrane antigen (PSMA) and prostate stem cell antigen (PSCA) being widely expressed in the tissue of PCa, no definite conclusion regarding their use as clinical biomarkers due to their lacking organ specificity. Therefore, this study aimed to evaluate the peripheral blood levels of PSMA and PSCA mRNAs and examine their diagnostic significance as non-invasive integrated markers.

Materials and Methods: 125 subjects were enrolled in this study. They were divided into 25 healthy controls, 25 BPH patients, and 75 PCa patients. The expression levels of PSMA and PSCA were determined using quantitative RT- PCR, in addition to measuring serum PSA.

Results: Levels of PSMA and PSCA were over-expressed in PCa patients compared to controls and BPH patients and were found to be associated with increased susceptibility to PCa. Moreover, the diagnostic values of PSMA and PSCA to distinguish PCa patients from BPH patients and controls were inferior to that of PSA. However, the combination of PSMA and PSCA with PSA enhanced the efficacy of the latter.

Conclusion: This study suggests that these genes were associated with malignant susceptibility. Concerning the duality of PSMA-PSA or PSCA-PSA, this implies the significance of their investigation together in peripheral blood of prostate patients.


Assuntos
Hiperplasia Prostática , Neoplasias da Próstata , Masculino , Humanos , Antígeno Prostático Específico , Hiperplasia Prostática/diagnóstico , Hiperplasia Prostática/genética , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Neoplasias da Próstata/diagnóstico , Neoplasias da Próstata/genética , Neoplasias da Próstata/metabolismo , Próstata/patologia , Antígenos de Neoplasias/genética , Proteínas de Neoplasias , Proteínas Ligadas por GPI
7.
Int Emerg Nurs ; 65: 101218, 2022 11.
Artigo em Inglês | MEDLINE | ID: mdl-36395754

RESUMO

BACKGROUND: Workplace violence against emergency nurses is an alarming hazard in Jordan, as it is globally. There is no prior research exploring the experiences of workplace violence against Jordanian emergency nurses. This study aimed to investigate Jordanian emergency registered nurses' lived experiences of workplace violence from their patients or relatives while working. METHOD: A descriptive phenomenological study was conducted using Colaizzi's data analysis method. Twelve emergency nurses participated in this study and were recruited via two Facebook groups using purposeful sampling. RESULTS: Four themes emerged from the analysis of violence in the emergency department revealed in this phenomenological study: (1) feeling overwhelmed that violence is so common, (2) ambivalent feelings toward patients and their families, (3) The feeling of inadequacy in handling violent situations, and (4) nurses' suffering. DISCUSSION: The findings of this study have practical implications for in-service workplace training programs and may be used to inform potential changes to policies and legislation designed to establish a safer emergency department environment for nurses, patients and their relatives/visitors. CONCLUSION: The findings can help policymakers, healthcare leaders, and managers better understand the consequences of workplace violence to advocate for and establish workplace violence prevention programs and strategies to support nursing staff who have experienced these events.


Assuntos
Enfermeiras e Enfermeiros , Recursos Humanos de Enfermagem , Violência no Trabalho , Humanos , Jordânia , Local de Trabalho
8.
Children (Basel) ; 9(11)2022 Oct 22.
Artigo em Inglês | MEDLINE | ID: mdl-36360332

RESUMO

To investigate how plyometric exercise (PLYO-Ex) affects mechanics and morphometrics of the plantar flexor musculotendinous unit in children with unilateral cerebral palsy, 38 participants (aged 10-16 years) were allocated at random to either the PLYO-Ex group (n = 19; received 24 sessions of plyometric muscle loading, conducted 2 times a week for 3 months in succession) or the control group (n = 19; underwent traditional physical therapy for the same frequency and duration). Measurements were taken pre- and post-intervention. Standard ultrasound imaging was applied to evaluate morphometrics of the gastrocnemius muscle and Achilles tendon unit and an isokinetic dynamometer was used to evaluate maximum voluntary isometric plantar flexors contraction (IVCmax). With controlling for pre-treatment values, significant post-treatment changes favoring the PLYO-Ex group were observed for morphological (tendon (p = 0.003, η2p = 0.23) length; belly length (p = 0.001, η2p = 0.27); tendon thickness (p = 0.035, η2p = 0.35); muscle thickness (p = 0.013, η2p = 0.17); fascicle length (p = 0.009, η2p = 0.18); pennation angle (p = 0.015, η2p = 0.16)) and mechanical and material properties (IVCmax (p = 0.009, η2p = 0.18); tendon's elongation (p = 0.012, η2p = 0.17), stiffness (p = 0.027, η2p = 0.13); stress (p = 0.006, η2p = 0.20); strain (p = 0.004, η2p = 0.21)). In conclusion, plyometric exercise induces significant adaptations within the musculotendinous unit of the plantar flexors in children with unilateral cerebral palsy. These adaptations could improve muscular efficiency and consequently optimize physical/functional performance.

9.
RSC Adv ; 12(31): 20156-20173, 2022 Jul 06.
Artigo em Inglês | MEDLINE | ID: mdl-35919614

RESUMO

A new approach has been developed for environmentally friendly C-C cross-coupling reactions using bi-functional Pd(ii)-salen complex-embedded cellulose filter paper (FP@Si-PdII-Salen-[IM]OH). A Pd(ii)-salen complex bearing imidazolium [OH]-moieties was covalently embedded into a plain filter paper, then used as an efficient portable catalyst for the Heck, Suzuki, and Sonogashira cross-coupling reactions under environmentally friendly conditions via the filtration method. The catalytic filter paper properties were studied by EDX, XPS, TGA, ATR, XRD, and FESEM analyses. The reactions were catalyzed during reactants' filtration over the catalytic filter paper. The modified filter paper was set up over a funnel and the reactants were passed through the catalytic filter paper several times. The effect of reaction parameters including loading of Pd(ii)-salen complex, temperature, solvent, and contact time were carefully studied and also the optimal model of conditions was presented by the design expert software. High to excellent yields were obtained for all C-C coupling types with 5 to 8 filtration times. Under optimal conditions, all coupling reactions showed high selectivity and efficiency. Another advantage of the modified filter paper was its stability and reusability for several times with preservation of catalytic activity and swellability.

10.
Curr Med Imaging ; 19(5): 486-493, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35927895

RESUMO

BACKGROUND: Chest High-Resolution Computed Tomography (HRCT) is mandatory for patients with confirmed Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection and a high Respiratory Rate (RR) because sublobar consolidation is the likely pathological pattern in addition to Ground Glass Opacities (GGOs). OBJECTIVE: The present study determined the correlation between the percentage extent of typical pulmonary lesions on HRCT, as a representation of severity, and the RR and peripheral oxygen saturation level (SpO2), as measured through pulse oximetry, in patients with Reverse Transcriptase Polymerase Chain Reaction (RT-PCR)-confirmed primary (noncomplicated) SARS-CoV-2 pneumonia. METHODS: The present retrospective study was conducted in 332 adult patients who presented with dyspnea and hypoxemia and were admitted to Prince Mohammed bin Abdulaziz Hospital, Riyadh, Saudi Arabia between May 15, 2020 and December 15, 2020. All the patients underwent chest HRCT. Of the total, 198 patients with primary noncomplicated SARS-CoV-2 pneumonia were finally selected based on the typical chest HRCT patterns. The main CT patterns, GGO and sublobar consolidation, were individually quantified as a percentage of the total pulmonary involvement through algebraic summation of the percentage of the 19 pulmonary segments affected. Additionally, the statistical correlation strength between the total percentage pulmonary involvement and the age, initial RR, and percentage SpO2 of the patients was determined. RESULTS: The mean ± Standard Deviation (SD) age of the 198 patients was 48.9 ± 11.4 years. GGO magnitude alone exhibited a significant weak positive correlation with patients' age (r = 0.2; p = 0.04). Sublobar consolidation extent exhibited a relatively stronger positive correlation with RR than GGO magnitude (r = 0.23; p = 0.002). A relatively stronger negative correlation was observed between the GGO extent and SpO2 (r = - 0.38; p = 0.002) than that between sublobar consolidation and SpO2 (r = - 0.2; p = 0.04). An increase in the correlation strength was demonstrated with increased case segregation with GGO extent (r = - 0.34; p = 0.01). CONCLUSION: The correlation between the magnitudes of typical pulmonary lesion patterns, particularly GGO, which exhibited an incremental correlation pattern on chest HRCT, and the SpO2 percentage, may allow the establishment of an artificial intelligence program to differentiate primary SARS-CoV-2 pneumonia from other complications and associated pathology influencing SpO2.


Assuntos
COVID-19 , SARS-CoV-2 , Humanos , Adulto , Pessoa de Meia-Idade , COVID-19/diagnóstico por imagem , Estudos Retrospectivos , Inteligência Artificial , Saturação de Oxigênio , Tomografia Computadorizada por Raios X/métodos
11.
Appl Radiat Isot ; 187: 110348, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-35779304

RESUMO

PURPOSE: This study aimed to determine the radioprotective effect of N-acetylcysteine (NAC) on the radiation-induced oxidative stress (OS) in the rats' brainstem. MATERIALS AND METHODS: Eighty rats in four identical groups, including vehicle control (VC), irradiation alone (RAD), irradiation with 1 g/kg of NAC treatment (RAN), and NAC treatment without radiation (NAC) were used. Whole-brain irradiation was performed with a single dose of 25 Gy. The rats received the treatments via intraperitoneal (IP) injection 1 h before the irradiation process. Nitric oxide (NO), malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT), total antioxidant capacity (TAC), and glutathione peroxidase (GPx) were measured in the rats' brainstem and compared between the groups. Furthermore, the pathological study was performed to assess tissue damage after 24 h, 72 h, and 5 days of irradiation. RESULTS: The levels of NO and MDA in the brainstem tissue for the RAD group were 60.37 ± 3.35 µmol/L and 45.10 ± 2.48 µM, respectively, which were higher than those of VC group (NO: 30.41 ± 1.83 µmol/L; MDA: 31.02 ± 1.71 µM). The level of SOD, CAT, TAC, and GPx declined in the RAD compared to the VC group. Pre-treatment with NAC decreased the level of NO and MDA and also enhanced the antioxidant activities. The greatest pathological changes in the rats' brainstems were seen in RAD animals compared to the VC group at 24 h, 72 h, and 5 days. Furthermore, the pathological changes were not observed in the NAC group in all the assessed times. CONCLUSION: Based on the results, NAC can decrease the irradiation-induced oxidative stress and pathology damages in the rats' brainstem. It can be concluded that NAC can be an appropriate radioprotection candidate for the human brainstem.


Assuntos
Acetilcisteína , Antioxidantes , Tronco Encefálico , Protetores contra Radiação , Acetilcisteína/farmacologia , Animais , Antioxidantes/metabolismo , Tronco Encefálico/metabolismo , Tronco Encefálico/efeitos da radiação , Glutationa Peroxidase/metabolismo , Malondialdeído/metabolismo , Protetores contra Radiação/farmacologia , Ratos , Superóxido Dismutase/metabolismo , Raios X/efeitos adversos
12.
Nanomaterials (Basel) ; 12(9)2022 May 09.
Artigo em Inglês | MEDLINE | ID: mdl-35564313

RESUMO

This study aims to study the discharging process to verify the influence of geometry modifications and heat transfer flow (HTF) patterns on the performance of a vertical triplex-tube latent heat container. The phase change material (PCM) is included in the middle tube, where the geometry is modified using single or multi-internal frustum tubes instead of straight tubes to enhance the discharging rate. The effects of the HTF flow direction, which is considered by the gravity and opposite-gravity directions, are also examined in four different cases. For the optimal geometry, three scenarios are proposed, i.e., employing a frustum tube for the middle tube, for the inner tube, and at last for both the inner and middle tubes. The effects of various gap widths in the modified geometries are investigated. The results show the advantages of using frustum tubes in increasing the discharging rate and reducing the solidification time compared with that of the straight tube unit due to the higher natural convection effect by proper utilization of frustum tubes. The study of the HTF pattern shows that where the HTF direction in both the inner and outer tubes are in the gravity direction, the maximum discharging rate can be achieved. For the best configuration, the discharge time is reduced negligibly compared with that for the system with straight tubes which depends on the dimensions of the PCM domain.

13.
RSC Adv ; 12(18): 10933-10949, 2022 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-35425081

RESUMO

A reductive filter paper for selective nitro reduction has been prepared by modification of a pristine cellulose filter paper by Pd/C nanoparticles, as a portable catalyst. The reaction was performed in two different set-ups including (i) filtration and (ii) sealed systems, in the presence of ammonium formate and ex situ generated hydrogen gas reducing agents, respectively. In the sealed system in the presence of H2 gas, the halogenated nitroarenes were completely reduced, while in the filtration system, different derivatives of the nitroarenes were selectively reduced to aryl amines. In both systems, the reduction of nitroarenes to aryl amines was performed with high efficiency and selectivity, comparable to a heterogeneous system. Reaction parameters were comprehensively designed using Design Expert software and then studied. The properties of the catalytic filter paper were studied in detail from the points of view of swellability, shrinkage, reusability, and stability against acidic, alkaline, and oxidative reagents.

14.
Anal Methods ; 14(13): 1301-1310, 2022 03 31.
Artigo em Inglês | MEDLINE | ID: mdl-35318477

RESUMO

The human epidermal growth factor receptor 2 (HER-2) protein is a member of the epidermal growth factor receptor (EGFR or ErbB) family and is a transmembrane tyrosine kinase receptor. HER-2 is highly regulated in ovarian, lung, gastric, oral, and breast cancers. The low specificity, complexity, expensiveness and the lack of sensitivity are essential restrictions in traditional diagnosis methods such as FISH, immunohistochemistry and PCR and these disadvantages led to the need for more studies on alternative methods. Biosensor technology has greatly affected the quality of human life owing to its features including, sensitivity, specificity, and rapid diagnosis and monitoring of different patient diseases. In this review article, we examine various biosensors, considering that they have been categorized based on the transducers used including piezoelectric biosensors, optical sensors such as fluorescence and surface plasmon resonance, and electrochemical types for the diagnosis of HER-2 and the effectiveness of some drugs against that. Attention to developing some types of biosensor devices such as colorimetric biosensors for HER-2 detection can be an important point in future studies.


Assuntos
Técnicas Biossensoriais , Neoplasias , Biomarcadores Tumorais , Técnicas Biossensoriais/métodos , Técnicas Eletroquímicas/métodos , Humanos , Neoplasias/diagnóstico , Receptor ErbB-2/genética
15.
Nanomaterials (Basel) ; 12(3)2022 Jan 26.
Artigo em Inglês | MEDLINE | ID: mdl-35159751

RESUMO

Employing phase-change materials (PCM) is considered a very efficient and cost-effective option for addressing the mismatch between the energy supply and the demand. The high storage density, little temperature degradation, and ease of material processing register the PCM as a key candidate for the thermal energy storage system. However, the sluggish response rates during their melting and solidification processes limit their applications and consequently require the inclusion of heat transfer enhancers. This research aims to investigate the potential enhancement of circular fins on intensifying the PCM thermal response in a vertical triple-tube casing. Fin arrays of non-uniform dimensions and distinct distribution patterns were designed and investigated to determine the impact of modifying the fin geometric characteristics and distribution patterns in various spatial zones of the heat exchanger. Parametric analysis on the various fin structures under consideration was carried out to determine the most optimal fin structure from the perspective of the transient melting evolution and heat storage rates while maintaining the same design limitations of fin material and volume usage. The results revealed that changing the fin dimensions with the heat-flow direction results in a faster charging rate, a higher storage rate, and a more uniform temperature distribution when compared to a uniform fin size. The time required to fully charge the storage system (fully melting of the PCM) was found to be reduced by up to 10.4%, and the heat storage rate can be improved by up to 9.3% compared to the reference case of uniform fin sizes within the same fin volume limitations.

16.
J Colloid Interface Sci ; 610: 879-892, 2022 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-34865739

RESUMO

Herein, two distinct nanocomposites of CaTiO3 micro-cubes and polygonal SrFe12O19, both decorated with NiO nanoparticles, were successfully synthesized using hydrothermal method. The physico-chemical features of as-prepared samples were evaluated via XRD, FTIR, UV-vis, BET, XPS, FESEM and EDS analysis. Microwave attenuation features of as-prepared single layer absorbers were determined by VNA analysis in 2-18 GHz. Simulation confirmation was checked by preparing a bi-layer samples and evaluating it using VNA analysis after finding the appropriate thickness of each layer. The reflection loss from each single layer samples containing 20 wt% of each CaTiO3/NiO and SrFe12O19/NiO nanocomposites were -16 dB and -35 dB at 6.3 GHz with 2.5 mm matching thickness respectively. However, the RL was -34 dB at 10 GHz frequency with 2 mm thickness in a bilayer absorber with SrFe12O19/NiO nanocomposite layer put as absorbing layer with 1 mm thickness and CaTiO3/NiO positioned as matching layer with 1 mm thickness. Furthermore, at the X-band frequency, approximately entire band absorption is obtained. The findings demonstrate that adjusting the order and thickness of the layers in a bilayer absorber may readily improve microwave absorption performance. By comparing the results of simulation with real prepared bilayer absorbers, we found that with a 2 mm overall thickness, the bi-layer absorbers display accurate RL values, but not the matching frequency monitored in the simulation process. In reality, this discrepancy was unavoidable.


Assuntos
Nanocompostos , Micro-Ondas
17.
Nanomaterials (Basel) ; 11(12)2021 Nov 26.
Artigo em Inglês | MEDLINE | ID: mdl-34947559

RESUMO

Thermal energy storage is an important component in energy units to decrease the gap between energy supply and demand. Free convection and the locations of the tubes carrying the heat-transfer fluid (HTF) have a significant influence on both the energy discharging potential and the buoyancy effect during the solidification mode. In the present study, the impact of the tube position was examined during the discharging process. Liquid-fraction evolution and energy removal rate with thermo-fluid contour profiles were used to examine the performance of the unit. Heat exchanger tubes are proposed with different numbers and positions in the unit for various cases including uniform and non-uniform tubes distribution. The results show that moving the HTF tubes to medium positions along the vertical direction is relatively better for enhancing the solidification of PCM with multiple HTF tubes. Repositioning of the HTF tubes on the left side of the unit can slightly improve the heat removal rate by about 0.2 in the case of p5-u-1 and decreases by 1.6% in the case of p5-u-2. It was found also that increasing the distance between the tubes in the vertical direction has a detrimental effect on the PCM solidification mode. Replacing the HTF tubes on the left side of the unit negatively reduces the heat removal rate by about 1.2 and 4.4%, respectively. Further, decreasing the HTF temperature from 15 °C to 10 and 5 °C can increase the heat removal rate by around 7 and 16%, respectively. This paper indicates that the specific concern to the HTF tube arrangement should be made to improve the discharging process attending free convection impact in phase change heat storage.

18.
Nanomaterials (Basel) ; 11(11)2021 11 22.
Artigo em Inglês | MEDLINE | ID: mdl-34835917

RESUMO

Due to the potential cost saving and minimal temperature stratification, the energy storage based on phase-change materials (PCMs) can be a reliable approach for decoupling energy demand from immediate supply availability. However, due to their high heat resistance, these materials necessitate the introduction of enhancing additives, such as expanded surfaces and fins, to enable their deployment in more widespread thermal and energy storage applications. This study reports on how circular fins with staggered distribution and variable orientations can be employed for addressing the low thermal response rates in a PCM (Paraffin RT-35) triple-tube heat exchanger consisting of two heat-transfer fluids flow in opposites directions through the inner and the outer tubes. Various configurations, dimensions, and orientations of the circular fins at different flow conditions of the heat-transfer fluid were numerically examined and optimized using an experimentally validated computational fluid-dynamic model. The results show that the melting rate, compared with the base case of finless, can be improved by 88% and the heat charging rate by 34%, when the fin orientation is downward-upward along the left side and the right side of the PCM shell. The results also show that there is a benefit if longer fins with smaller thicknesses are adopted in the vertical direction of the storage unit. This benefit helps natural convection to play a greater role, resulting in higher melting rates. Changing the fins' dimensions from (thickness × length) 2 × 7.071 mm2 to 0.55 × 25.76 mm2 decreases the melting time by 22% and increases the heat charging rate by 9.6%. This study has also confirmed the importance of selecting the suitable values of Reynolds numbers and the inlet temperatures of the heat-transfer fluid for optimizing the melting enhancement potential of circular fins with downward-upward fin orientations.

19.
Sci Rep ; 11(1): 20476, 2021 10 14.
Artigo em Inglês | MEDLINE | ID: mdl-34650073

RESUMO

The increased frequency of neurological manifestations, including central nervous system (CNS) manifestations, in patients with coronavirus disease 2019 (COVID-19) pandemic is consistent with the virus's neurotropic nature. In most patients, brain magnetic resonance imaging (MRI) is a sensitive imaging modality in the diagnosis of viral encephalitides in the brain. The purpose of this study was to determine the frequency of brain lesion patterns on brain MRI in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pneumonia patients who developed focal and non-focal neurological manifestations. In addition, it will compare the impact of the Glasgow Coma Scale (GCS) as an index of deteriorating cerebral function on positive brain MRIs in both neurological manifestations. This retrospective study included an examination of SARS-CoV-2 pneumonia patients with real-time reverse transcription polymerase chain reaction (RT-PCR) confirmation, admitted with clinicoradiologic evidence of COVID-19 pneumonia, and who were candidates for brain MRI due to neurological manifestations suggesting brain involvement. Brain imaging acquired on a 3.0 T MRI system (Skyra; Siemens, Erlangen, Germany) with a 20-channel receive head coil. Brain MRI revealed lesions in 38 (82.6%) of the total 46 patients for analysis and was negative in the remaining eight (17.4%) of all finally enclosed patients with RT-PCR confirmed SARS-CoV-2 pneumonia. Twenty-nine (63%) patients had focal neurological manifestations, while the remaining 17 (37%) patients had non-focal neurological manifestations. The patients had a highly significant difference (p = 0.0006) in GCS, but no significant difference (p = 0.4) in the number of comorbidities they had. Brain MRI is a feasible and important imaging modality in patients with SARS-CoV-2 pneumonia who develop neurological manifestations suggestive of brain involvement, particularly in patients with non-focal manifestations and a decline in GCS.


Assuntos
Encefalopatias/etiologia , Encéfalo/diagnóstico por imagem , COVID-19/complicações , Adulto , Idoso , Encéfalo/patologia , Encefalopatias/diagnóstico por imagem , Encefalopatias/patologia , COVID-19/patologia , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , SARS-CoV-2/isolamento & purificação
20.
Ann Med Surg (Lond) ; 67: 102527, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34276981

RESUMO

BACKGROUND: Choosing future specialty is an important issue that face undergraduate medical students during their university years. Several factors may assist to formulate students' final decision. We aimed to explore the future specialty preferences and the factors that influence the choice of undergraduate students in medical schools in Jordan. METHODS: A cross sectional study conducted among the sixth year students of two medical schools in Jordan. A questionnaire was used to collect data from the students. It consisted of demographic data in form of gender, GPA, family income, and parents' level of education. In addition to data about preferred specialties, and factors that influence medical students' choice of future specialty. RESULTS: A total of 223 medical students from two medical schools were recruited to participate. Males were 49.3% while females were 50.7%, and around 22% scored an excellent GPA. Most parents of the students were bachelor degree holders (63.6% for fathers and 62.3% for mothers). Medicine (19.4%), dermatology (12.6%), and obstetrics and gynecology (11.7%) were the most chosen future specialties. Specialty appeal and thoughts of future creativity was the most chosen factor that influenced future specialty (55.2%) choice, followed by family time and less on-call duties (14.8%). Students who selected chances of fellowships as an influencing factor were more likely to prefer medicine as future specialties (p < 0.001). CONCLUSION: Medicine, dermatology, and obstetrics and gynecology were the most popular future specialty choices among undergraduate medical students. Most of our medical students claimed that selection of their specialty is based on the interest and potential creativity, family time and less on call duties. Further studies are required in a wide range to accommodate more students from the other academic years.

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